Abstract
The purpose of pedodontic practice is to contribute to the growth and development of the whole body of the child. It is said that the oral function is established by 1 year and 6 months before the deciduous dentition is completed and after that completion, dental caries, periodontal disease and malocclusions etc appear and then, they act as elements for destroying the normal oral function.
Therefore, it is considered that the earlier oral disease appear, the worse the influences are on the growth and development of the oral function.
There are many reports on the dental caries, but on the other hand there have been few studies on the occlusion in the primary dentition so that it is an open field for research. The present authors observed the changes of malocclusion at the age of 2 to 3 and 3586 cases were investigated as a cross-section and 1270cases were followed up over a peroid of time.
The results obtained are summarized as follows:
1. It was found that incidence of the malocclusion that occurred at 2 years of age was 49.8% and at 3 years of age was 42.1%.
2. Malocclusions observed at the ages of 2 and 3 were listed in order of the most frequent occurrence.
1) deep over-bite
2) anterior cross-bite
3) open bite
4) crowdeing
5) anterio-posterior cross-bite
6) posterior cross-bite
3. There were tendencies in the changes of malocclusion at the age of 2 and 3 in that the anterior cross-bites and the deep over-bite decreased, while the anterioposterior cross-bites increased and there were no changes of the antrio-posterior cross-bites, open bites and crowdings.
4. The persentages of those malocclusion spontaneously impoving and changing in to normal occlusions from the age of 2 to 3 were as follows:
anterior cross-bite 42.0%
anterio-posterior cross-bite 40.0%
open bite 56.1%crowding 56.9%
deep over-bite 44.4%
5. The cases in which the normal occulusin at the age of 2 were spontaneously growing worse and changing in to malocclusins at the age of 3 amounted to 60.4% and also worse crowdings appeared in 61.5% of the cases.
